Qualcomm on Wednesday said its quad-core Snapdragon chips, designed to run Microsoft's upcoming Windows 8 OS, will appear in tablets in the second half of next year.

The quad-core chips will be part of the Snapdragon S4 product line and are based on the ARM architecture. The S4 chips, which will also include single-core and dual-core options, will run at clock speeds between 1.5GHz and 2.5GHz.

Microsoft has said Windows 8 will work with ARM processors and has chosen Qualcomm, Texas Instruments and Nvidia as initial chip partners. Tablets with S4 chips will run Windows 8, Qualcomm spokeswoman Catherine Rice said. The chip's Adreno graphics core will support DirectX 9.3, which will be found in Windows 8 to bring realistic graphics to devices.

Rice declined to comment on the release date for S4 tablets with Windows 8. Microsoft has already demonstrated Windows 8 running on a Snapdragon tablet.

Microsoft hasn't announced a release date for Windows 8. However, Intel has said the OS will be released later next year, which could be around the time the first S4 tablets are released.

Snapdragon chips are already being used in HTC's Jetstream and Lenovo's IdeaPad U1 tablets. Qualcomm is working with 30 tablet designs with top device makers, Rice said.

Qualcomm will compete with Nvidia, which has already shipped a quad-core ARM processor for tablets. Asustek Computer last week announced the Eee Pad Transformer Prime tablet, which has a 10-inch screen and the Tegra 3 quad-core processor. Analysts have said the Asus tablet could be the fastest among a crop of dual-core tablets currently available.

Windows 8 on ARM is a big opportunity to sell more chips on laptops and tablets, especially with low mobile-broadband penetration on those devices, said Derek Aberle, group president at Qualcomm, during an analyst day meeting on Wednesday, which was webcast.

The S4 includes an integrated 3G and 4G modem, which gives Qualcomm a leg up over competition. Nvidia and Texas Instruments do not yet integrate modems inside processor chips.

The integration of a modem, graphics processors and other units helps reduce the size and power consumption of the Snapdragon S4, said Dean McCarron, principal analyst at Mercury Research. The quad-core chip will be made using the 28-nanometer process, which will improve performance while reducing power consumption.

As a result, tablets with S4 chips could be thinner and more power efficient.

"When it's on the same die, it lets you be a little more compact," McCarron said.

Like Windows 7, Windows 8 can take advantage of chips with a larger number of ARM accelerators and cores.

"The newer the OS, the more likely it is going to be able to deal with multithreading," McCarron said.

But there are questions on the necessity of quad-core chips because dual-core chips meet most tablet needs, McCarron said. Quad-core chips are under 10 percent of the PC market volume and that trend could trickle into tablets.

The first S4 chip is the dual-core MSM8960, which is already being tested by device makers.

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